154 BULLETIN 76, UNITED STATES NATIONAL MUSEUM. 



found in the structure of the abactinal, marginal, and actinal intermediate plates, 

 the form of the adambukcral plates, the absence of superambulacral ossicles, the 

 form of the tube feet with their well developed sucking soles or disks. The adam- 

 bulacral armature is not unlike that of Gephijreasier (described in this report), which 

 is an annectant genus near Pseudarchaster and Mimaster. The abactinal para- 

 paxilliT, which are the sole "Archasterid " reminders, are not true paxillse and are 

 similar in structure to those of Mediaster, Nympliaster, and allied genera, which no 

 one would think of placing in the old Archasteridse. Professor Verrill's course has 

 in a measure cut the Gordian knot, and the genera are far better in a separate 

 family than in the Goniasteridaj. 



Genus ODONTASTER Verrill. 



Odontaster Verrill, Amer. Jouni. Sci., vol. 20, 1880, p. 402. Type 0. hispidus Verrill; Proc. U. S. 



Nat.Mua., vol. 17, 1894, p. 262; Amer. Journ. Sci., vol. 49, 1895, p. 136; Trans. Conn. Acad., 



vol. 10, 1899, p. 205 (restricted).— Bell (part), Proc. Zool. Soc. Lond., 1893, pp. 259-262.— 



LuDwio, Zeitschr. Wisa. Zool., 1905, p. 42. 

 Gnathasler Sladen (part). Challenger Asteroidea, 1889, p. 285. — Perkier, Exped. sci. du 



TravaillcuT et du Talisman, 1894, p. 244.— Verrill, Trans. Conn. Acad., vol. 10, 1899, 



p. 204 (restricted to inerulionalis, penicillatus, and ffrayi). 

 Acodontaskr Verrill, Trana. Conn. Acad., vol. 10, 1899, p. 204 (for Gnalhaster elongatus Sladen 



and Astrogonium miliare Gray). 



Diagnosis. — One odd, median, hyaline, more or less movable recurved spine 

 on each pair of prominent mouth plates, which may be close together or separated 

 by an open fusiform space covered with membrane. An odd triangular interradial 

 plate in both marginal series. Marginal plates usually prominent, decreasing in 

 size distally, and covered with granules or short spinelets. Abactinal plates more 

 or less paxilliform, often stellate, arranged in series parallel with the radial, also in 

 obli(iue transverse rows on rays ; papulae single, in the angles around radial paxillse, 

 and sometimes in center of disk. Adambulacral plates small, wider than long, 

 with straight furrow margin as in Goniasteridse. Furrow spinelets two to five, 

 and several longitudinal rows of two or tliree on the surface of plate. Actinal 

 intermediate areas broad, the plates in regular series parallel with furrow, and 

 covered with granuliform spinelets or well-developed spinelets. Simple pedicel- 

 lariae sometimes present. Superambulacral plates absent. Tube feet with well- 

 developed sucking disk. 



Bemarlis. — The genus as here defined includes the restricted genera Odontaster, 

 Gnalhaster, and Acodontasttr recognized by Verrill in 1899. It does not include 

 Asterodon Perrier, nor Diplodontias Fisher {Goniodon Perrier). 



ODONTASTER CRASSDS Fisher. ' 



PI. 29, figs. 1^; pi. 56, fig. 6. 

 Odontaster crassus Fisher, Bull. Bur. Fisheries for 1904, vol. 24, June 10, 1905, p. 302 

 Diagnosis.— yie&rly related to 0. grayi Bell. R = 21 mm. ; r = 1.3 mm. ; R = 1 .5 r. 

 Breadth of ray at base 15 mm. Form stellato-pentagonal with distinct rays, these 

 short and blunt ; disk large. Marginal plates massive, the superomarginals forming 

 a raised broad border to abactinal area; eight to a ray, and covered with granuliform 

 spinelets; odd interradial plate large; inferomargmals less tumid than superomar- 

 ginals and granulation coarser. Abactinal plates paxilliform on papular areas and 

 lobed, with fifteen to twenty-three sj)inelcts on radial series. Papula? restricted to 



